Adjustable countersink



c. 0. BOSSE. ADJUSTABLE COUNTERSINK.

APPLICATION FILED JUNE 3. 1918.

1,346, 1. (355a Pat nt d July 13, 1920.

UNITED STATES PATENT ()FFICE.

CHARLES O. BOSSE, OF TACOMA, YVJLSHINGTON.

ADJUSTABLE GOUNTERSINK.

To all whom it may concern:

Be it known that I, CHARLns O. Bossn, a citizen of the United States, residing at Tacoma, in the county of Pierce and State of lVashington, have invented certain new and useful Improvements in Adjustable Countersinks; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to adjustable countersinks, and it relates more particularly to an improved countersink having adjustable and interchangeable cutters.

One object of this invention is to provide a tool of this character, that is especially adapted for use in connection with high speed machines.

Another object is to provide a tool of this character in which each of the cutter seats combine with the cutters base for increasing the resistance in proportion to the increase of pressure, thereby relievingthe adjusting means from excessive pressure or strain during operation of the tool.

Another object is to provide a tool of this character which is capable of being quickly and easily adjusted while in its working en agement with a drill-chuck or socket.

Another object is to provide a tool of this character which is composed of few and simple parts and is, therefore, capable of being manufactured at a comparatively low cost; and,

Another object is to provide a tool of this character which is strong, durable, efficient and thoroughly practical.

Other objects or advantages may become apparent to persons who read the following details of description in connection with the accompanying drawings in which- Figure 1 is a view partly in section and partly in elevation, illustrating the preferred embodiment of this invention;

Fig. 2- is a front end elevation;

Fig. 3 is a transverse sectional View along the line 3-3 of Fig. 1; and,

Fig. 1 is a perspective View of one of the cutters or cutter blades which are interchangeably and adjustably seated in the main portion or body of the device.

Referring to these drawings in detail in which similar reference characters correspond with similar parts throughout the Specification of Letters Patent. Pat t J 13 1920. Application filed June 3, 1918.

Serial No. 237,997.

several views, the body or blade carrying head 5 of the tool is preferably cylindrical except lts front end which is conical or frust'o-conical as indicated at 6; a tapering shank 7 being integral with the cylindrical portlon 5 and extending from the rear end that is the end opposite to the conical end 6. Although the shank 7 is here illustrated as being tapered, it is to be understood that any appropriate form of shank 7 may be employed so that the tool may be fitted to and carried by different shapes and sizes of chucks and sockets. Moreover, the body 5 is formed with any preferred number of outwardly converging slots 8 which extend from end to end of the combined cylindrical portion and conical portion. Each slot 8 has its bot tom surface extending from a point adjacent the axial center of the cone-shaped end 6 to a point adjacent to the periphery of the cylindrical portion 5 at the end opposite to said cone-shaped portion, said bottom surface being inclined rearwardly and outwardly from the axis of rotation. Moreover the cylindrical portion 5 is provided with screw-seats 9 each of which is in open communication with one of the slots 8. Each ofthe screw-seats 9 consists of two series of screwthreaded-segments which are complemental to one another and extend substantially parallel with the adjacent inclined surface 10 of the communicating slot 8.

Within each of the slots 8 is seated a cutter blade 11 such as illustrated separately in Fig. 4. Each of these cutter blades is preferably formed of high-speed steel and has parallel inner and outer edges 12 and 13, respectively the latter being narrower than the former; or, in other words, each blade 11 tapers outwardly from its inner edge or basal surface so as to conform with the outwardly converging sides of the slots e. Each cutter or blade 11 is provided with a cutting edge 14 which is substantially parallel with the cone elements of the portion 6 of the body 5. The cross section of each blade is the same at all points between its curved rear end and its cutting edge 14, and the sides are plane and smooth, as shown in Fig. l. The rear end 15 of each blade 11 is substantially at right angles to the edges 12 and 18, so that it is also at right angles to the axis of a screw 16 which is seated in the corresponding screw-seat 9 and bears against this rear end 15 of the blade 11 and combines with the forwardly inclined surface 10 for resisting rearward movement of the-blade when working pressure is applied thereto, It is to be understood that there is one of the screws 16 for each one of the blades 11, each of these screws being seated in a corresponding oneiofthe screw-seats 9.

In order to adjust I 9 are turned in their seats so as to move the blades forward or allow them to be moved backward, according to the attending requirements.

When it is desired to remove one of the blades 1.1, its removal may be effected by sliding it forward out of the slot 8, or by removing the corresponding screw 16 and then sliding the blade backward. However, the blades may be sharpened without removing them from the body 5, and they may be successively and continually worn and sh arpened until the greater portion of them is removed, and the remainnig portions will operate as effectively as they did when the blades were new. This is true because each blade is of the same material and temper throughout its length. It is to ,be understood that the blades 11 are normally held in the grooves 8 by the frictional contact of their sides with the sides of the slots 01 grooves 8, proper care being taken to fit the blades tight enough in the slots to avoid their accidental displacement, but not so tight as to prevent them from being adjusted by the adjusting screws 16.

Attention is directed to the fact that the bottoms of the slots or grooves S, converge forwardlysubstantially to the apex of the conical front end of the body .5. The front ends of the grooves, however, terminate in slightlyxspaced relation and thus it will be seen that the several blades 11 may be adjustedin such a manner as to project their pointed front ends a considerable distance beyond the front end of the body. 7 By this the blades 11 the screws adjustment, due to the convergence of the groove bottoms, the pointed ends of the cutters are caused to move toward each other, thus adjusting the device for countersinking unusually "small holes. When this adjustment is effected, the blades project a con- ;siderabledistance from the bodygbutno. ob-

jectionable vibration will then occur, since the work is light. When the blades are adjusted rearwardly for countersinking large holes, their cutting edges 14 are reinforced or backed up by the wallsof the grooves'8 and thus, even though heavy work is being done, no vibration will take place. 7

Although I have described this embodiment of my invention very specifically, it is not intended to limit thisinvention to these exact details of construction and arrangement of parts, but I am entitled to make minor changes within the scope of the :inventive idea disclosed in the foregoing description and following claims:

'lVha-t I claim as my invention is:

An adjustable countersink comprising a head having a substantially conical front end, said head having grooves from end to end whose bottoms converge toward the apex of said conical end but terminate in spaced relation, blades n said grooves with their inner edgessslidable along said bot-' toms thereof, andmeans for sliding said blades in said grooves; said blades having oblique cutting edges forming pointed front ends therefor, said p'ointedends being movable toward each other as said blades are projected forwardly from the head, due to said converging groove bottoms.

'In testimony whereof I have'hereunto set my hand.

, CHARLES 'o. Bossn WVitnesses V CARL KELLER, MYRTLE KmszLrNc. 

